Boot displays just one dot and hangs
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  1. #1
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    Boot displays just one dot and hangs

    The IDE hard disk of my old IBM R50p laptop failed, so I replaced it with a new IDE SSD (model PA25-32). I booted with a Fedora 28 LXDE live USB stick and installed Fedora 28 to my new SSD. When I try to boot, the system displays just one dot (a period) in the top left corner and hangs. I have to use the power button to reboot from that situation.

    When I boot again with Fedora 28 LXDE live USB stick, I can see that the files in the new SSD are intact. I tried to re-install GRUB several times, but I get always the same results, except if I use option "--disk-module=native" then boot hangs but it displays two dots!

    In the live USB stick Ican see that the SSD is in LBA48 mode:

    Code:
    [   10.059225] ata1.00: ATA-9: PA25-32, 20150807, max UDMA/133
    [   10.059228] ata1.00: 62377984 sectors, multi 0: LBA48
    The BIOS of my R50p is 1RETDIWW (3.14 ) and EC is 1RHT71WW-3.04. The BIOS is dated 20 Jan 2005. As far as I know, the EC (Embedded Controller) firmware is the latest possible and the latest BIOS was published 18 Jun 2007. The BIOS change logs do not show any changes to booting or handling disks.

  2. #2
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    Re: Boot displays just one dot and hangs

    I don't know what your current problem is but there may be a temporary workaround if the grub2 files in the /boot directory are fine. The Super Grub2 rescue disk contains the grub2 boot loader and numerous scripts to scan all disks for boot-able systems. It can boot any Linux system it finds using the grub.cfg configuration files, kernels and initrds it finds on the disks. It is only a 20MB download and requires an extra small USB flash drive.

    https://www.supergrubdisk.org/super-grub2-disk/

  3. #3
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    Re: Boot displays just one dot and hangs

    I created a bootable USB stick. I got into GRUB Rescue prompt and I could see my hard disk and its contents with the ls command. I issued the "set root=" and "set prefix=" commands to point them to my new SSD.

    But when I enter command "insmod normal", the system hangs, I have to use the power button to restart the system. That command should load normal.mod from my new SSD, but it hangs???

  4. #4
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    Re: Boot displays just one dot and hangs

    I created a bootable USB stick. I got into GRUB Rescue prompt and I could see my hard disk and its contents with the ls command. I issued the "set root=" and "set prefix=" commands to point them to my new SSD.
    I recommended the Super Grub2 rescue disk with which you don't have to set anything as it scans all disks for bootable systems. You don't need to type anything into a rescue prompt with the Super Grub 2.

    https://www.supergrubdisk.org/super-grub2-disk/

    But when I enter command "insmod normal", the system hangs, I have to use the power button to restart the system. That command should load normal.mod from my new SSD, but it hangs???
    Code:
    16.3.51 normal
    
    Command: normal [file]
    
        Enter normal mode and display the GRUB menu.
    
        In normal mode, commands, filesystem modules, and cryptography modules are automatically loaded, and the full GRUB script parser is available. Other modules may be explicitly loaded using insmod (see insmod).
    
        If a file is given, then commands will be read from that file. Otherwise, they will be read from $prefix/grub.cfg if it exists.
    
        normal may be called from within normal mode, creating a nested environment. It is more usual to use configfile (see configfile) for this.
    I have never used this command but apparently you just type normal to enter normal mode. If you have set the $root and $prefix correctly then it will read your grub.cfg.
    Last edited by amiga; 4th September 2018 at 07:03 PM.

  5. #5
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    Re: Boot displays just one dot and hangs

    Thanks for the tip for Super Grub2 rescue disk. However, it did not help me. I could get its menu, but most options caused the machine to hang without any error message. My biggest problem is *why* my install of Fedora 28 to the new SSD hangs on boot and how to fix it.

    Now I have a USB stick that boots into Grub rescue prompt. I can enter some commands and I hope it allows me to debug my installation. It's promising that at least the ls command works!

    The command "insmod normal" loads the module from the place that I have set previously with the "set prefix" command. So the commands that I issued are:

    Code:
    ls
    set root=(hd2,msdos2)
    set prefix=(hd2,msdos1)/grub2
    insmod normal <-- this hangs the machine!!!
    If I enter command "ls /" after command "set root=(hd2,msdos2)" then I get message "error: unknown filesystem". The root partition of my Fedora 28 installation on the new SSD is a LVM file system and the /boot partition is an ext4 file system (which GRUB2 recognizes as ext2). Should I try to install Fedora 28 to my new SSD without a LVM file system???

    Are there any commands in the Grub rescue prompt that could give me more informaton?

  6. #6
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    Re: Boot displays just one dot and hangs

    If I enter command "ls /" after command "set root=(hd2,msdos2)" then I get message "error: unknown filesystem". The root partition of my Fedora 28 installation on the new SSD is a LVM file system and the /boot partition is an ext4 file system (which GRUB2 recognizes as ext2).
    First of all you are trying to access the wrong partition. This is the source of your problems as explained below. Your /boot partition is (hd2,msdos1). It should be

    Code:
    set root=(hd2,msdos1)
    set prefix=(hd2,msdos1)/grub2
    normal
    You appear to be very confused about the meaning of 'root' in grub. This does not refer to the Linux root / partition at all. It refers to the root of the grub installation which in your case would be your /boot partition.

    This is the source of your problem. You have been trying to access the wrong partition which is an LVM partition which can' t be read without the lvm.mod module. This is why you get the message "error: unknown filesystem" and why your system hangs when you try to enter normal mode. However since you have a separate /boot partition you don't need to access the Linux root partition at all.

    The grub boot process only cares about the kernel, initrd, and grub.cfg. The partition that has these files is the grub root. If your /boot partition is msdos1 then

    Code:
    set root=(hd2,msdos1)
    Should I try to install Fedora 28 to my new SSD without a LVM file system???
    Second of all there is no such thing as a "LVM file system". LVM is a type of partitioning and not a file system. There is nothing wrong with having an LVM root partition. It itself isn't causing your problems.

    If you had given more information in your second post your problem could have been solved earlier.
    Last edited by amiga; 4th September 2018 at 06:51 PM.

  7. #7
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    Re: Boot displays just one dot and hangs

    Of course I have read your message. No, I don't feel very consused, I just feel curious. So let's get into the point:

    So in order to debug boot hangs in my fresh Fedora 28 installation on a new SSD in an old Thinkpad with an old BIOS, I have a USB stick which boots into GRUB2 Rescue mode. If I enter commands:

    Code:
    set root=(hd2,msdos1)
    set prefix=(hd2,msdos1)/grub2
    normal
    then I get message "Unknown command 'normal'"

    If I enter command "insmod normal" then the system just hangs and I have to use the power button.

    Maybe I should insmod another module before module normal?

    I guess the reason why boot hangs after installing Fedora 28 is an old BIOS which does not understand my SSD (maybe LBA48 mode is the problem)???

    Are there any commands in the Grub rescue prompt that could give me more informaton?

  8. #8
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    Re: Boot displays just one dot and hangs

    No, I don't feel very consused, I just feel curious.
    You were confusing the Linux / root partition and the grub root and accessing the wrong partition.

    After setting the root and prefix are you now able to view files on the SSD with ls ? Can you view the kernel, initrd ...

    If I enter command "insmod normal" then the system just hangs and I have to use the power button.
    Maybe I should insmod another module before module normal?
    You should insmod other modules such as part_msdos and ext2. You may need them.

    Are there any commands in the Grub rescue prompt that could give me more information?
    At this point you should post your grub.cfg. Throughout this thread you have haven't given enough information for others to deduce your problem. I didn't know that you were accessing the wrong partition until your third post. If the Super Grub2 menu entries didn't work for you it is likely there are errors in the grub.cfg.

    It may be necessary to re-install grub from a live usb environment using chroot.

    I guess the reason why boot hangs after installing Fedora 28 is an old BIOS which does not understand my SSD (maybe LBA48 mode is the problem)???
    Does your BIOS support LBA48 ? It was introduced in 2003 well before your BIOS.

  9. #9
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    Re: Boot displays just one dot and hangs

    When I boot with the USB stick that gives me the grub rescue prompt, I can use the ls command to view file names in the /boot partition (hd2,msdos1). The /boot partition seems to contain all the necessary files.

    Commands "insmod part_msdos" and "insmod ext2" seem to succeed. But if I enter command "insmod normal" after them, it will hang the machine. Also command "insmod gzio" hangs the machine. Why some modules load fine but others hang the machine???

    I see no point in posting my grub.cfg because I have tried so may variations of the "grub2-install" command in Fedora 28 Live USB stick. All of them hang, including the configuration created automatically by the Fedora 28 installer in the LIve image. Let's try to get the system boot manually in the grub rescue prompt first, maybe then we can use grub2-install to create a working configuration.

    I don't know whether the BIOS supports LBA48 or not.

  10. #10
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    Re: Boot displays just one dot and hangs

    When I boot with the USB stick that gives me the grub rescue prompt, I can use the ls command to view file names in the /boot partition (hd2,msdos1). The /boot partition seems to contain all the necessary files.
    This is good. This should mean you should be able to boot manually by specifying the kernel, initrd and the boot command as follows.

    Code:
    insmod part_msdos
    insmod ext2
    insmod lvm
    insmod linux16
    linux16 vmlinuz-file root=/dev/mapper/vg-name-lv-name ro rd.lvm.lv=vg-name/lv-name kernel-parameters
    initrd16 initrd-file
    boot

    Commands "insmod part_msdos" and "insmod ext2" seem to succeed. But if I enter command "insmod normal" after them, it will hang the machine. Also command "insmod gzio" hangs the machine. Why some modules load fine but others hang the machine?
    I have a theory about this. The grub version used by Fedora 28 which is 2.03 could be newer than the grub version of your 'bootable USB stick'. If you are trying to load modules from your new SSD which are grub 2.03 they may not work with the older grub version on your USB stick. The grub that comes with Fedora 28 is much more advanced than what came with Fedora 24 which was the last version I installed. if you are trying to insmod after you have set the root and prefix to your new SSD it may be trying to load new versions of modules into an older grub executable on your USB stick. Just like kernel modules must match the kernel for insmod it may be similar for grub2 and its modules.

    The modules which load successfully such as ext2 and part_msdos may not have changed. The ones that hang the system such as gzio may have changed.

    To get around this do not load any modules from your new SSD. Load all modules you may need with insmod before setting the root and prefix. This should load modules from the USB stick itself.

    I don't know whether the BIOS supports LBA48 or not.
    It must or you wouldn't have been able to install F28 in the first place, or read files in grub with ls, or insmod ext2 and part_msdos.
    Last edited by amiga; 5th September 2018 at 03:15 AM. Reason: added explanation

  11. #11
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    Re: Boot displays just one dot and hangs

    I tried to boot manually by entering the commands that you suggested - and of course I set the root and prefix first. The first two insmods succeeded as before, but the command "insmod lvm" caused the system hang!

    The ext4 file system in my SSD boot partition (hd2,msdos1) was created by the Fedora 28 Live stick. As it was running full Linux kernel, it used the SSD in LBA48 mode. If Grub2 rescue prompt is using BIOS and if the BIOS does not understand LBA48 mode, then the BIOS (and Grub) sees the disk geometry in a wrong way. Maybe some files (such as the root directory and part_msdos.mod and ext2.mod) look the same in LBA48 and non-LBA48 mode, but other files (such as normal.mod, gzio.mod and lvm.mod) look different in LBA48 and non-LBA48 modes, and that causes the hang? If so, how can I fix this?

  12. #12
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    Re: Boot displays just one dot and hangs

    I tried to boot manually by entering the commands that you suggested - and of course I set the root and prefix first. The first two insmods succeeded as before, but the command "insmod lvm" caused the system hang!
    Why did you do this ? Did you read the explanation in my previous message ?

    This is the opposite of what I suggested.

    To get around this do not load any modules from your new SSD. Load all modules you may need with insmod before setting the root and prefix. This should load modules from the USB stick itself.
    Why did you do the opposite of what I suggested and then say "of course I set the root and prefix first" ? I told you to load all modules with insmod before setting the root and prefix. The version of grub2 in Fedora 28, grub2 2.03 is likely newer than that of your USB stick.

    You have never told me what live USB stick you are using and what is its grub version. Please do this.

    The ext4 file system in my SSD boot partition (hd2,msdos1) was created by the Fedora 28 Live stick. As it was running full Linux kernel, it used the SSD in LBA48 mode. If Grub2 rescue prompt is using BIOS and if the BIOS does not understand LBA48 mode, then the BIOS (and Grub) sees the disk geometry in a wrong way. Maybe some files (such as the root directory and part_msdos.mod and ext2.mod) look the same in LBA48 and non-LBA48 mode, but other files (such as normal.mod, gzio.mod and lvm.mod) look different in LBA48 and non-LBA48 modes, and that causes the hang?
    At this point you are just making stuff up to match your original 'theory'. Why would your own BIOS not understand LBA-48 mode ? There are a lot of ifs in the above statement that aren't true.

    I gave a more reasonable explanation about the grub2 versions being different.

    If so, how can I fix this?
    First of all this isn't what is happening. Second if you followed the directions in my previous message you wouldn't load any modules from your new SSD as this may be causing the problem.

  13. #13
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    Re: Boot displays just one dot and hangs

    The goal is to make the laptop boot from the new SSD. Now it just displays one dot and hangs. In order to debug why it hangs, I'd like to execute grub commands one by one. I do not know how I could pause the Grub installation that is on the SSD in order to execute its commands one by one - if there is a key that I could press at boot time to enter the Grub rescue command prompt, please tell me!

    Now I can enter the Grub rescue prompt by booting with an USB stick that I created using the Fedora 28 live CD. So the Grub version is the same on the USB stick and on the SSD.

    So far my only theory is that the disk uses LBA48 mode and Grub does not understand it. So Grub sees the SSD geometry incorrectly, but for some reason (old BIOS?) ls works and I can insmod some modules but not all. How can I verify whether Grub and the SSD agree on the disk geometry? And if not, can I make Grub to use the correct geometry (or access mode or LBA48) or can I put the SSD in a compatibility mode?

    When installing Grub to my SSD I used grub2-install from Fedora 28 Live stick. I tried options --disk-module=biosdisk and --disk-module=native. They both hang, but native displays two dots instead of one!

    Is there any way to get more verbose error messages from Grub?

  14. #14
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    Re: Boot displays just one dot and hangs

    Now I can enter the Grub rescue prompt by booting with an USB stick that I created using the Fedora 28 live CD. So the Grub version is the same on the USB stick and on the SSD.
    You should have mentioned this much earlier, after my post #10. You have a habit of leaving out necessary information. Also if the grub2 version is the same there is no need to try to load any modules from the new SSD. All insmod operations should be performed before setting the root and prefix. This just loads them from the live usb.

    When installing Grub to my SSD I used grub2-install from Fedora 28 Live stick.
    If you installed grub manually as opposed to having the installer do it which partition did you install it to ? Did you install grub2 to msdos1 or msdos 2 ? You previously had confused the grub root with the Linux root.

    So far my only theory is that the disk uses LBA48 mode and Grub does not understand it.
    LBA48 mode was introduced with ATA-6 in 2003 and is still the current standard mode. GNU Grub2 came out in 2012. Why would grub not understand the current standard which is now 15 years old?
    Last edited by amiga; 11th September 2018 at 12:28 AM.

  15. #15
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    Re: Boot displays just one dot and hangs

    I found a debug option to grub2-install and found script bootinfoscript. I haven't solved the problem yet, but the debug options gave me more information on what is happening. But I still need help on solving the problem!

    I'll describe results of three tests here. As I described before, I booted Fedora 28 Live USB stick and installed Fedora 28 to my new SSD in the old Thinkpad R50p laptop. The installation succeeded without errors, but it won't boot from the SSD. So I booted into the Live USB stick again and issued command:

    Code:
    grub2-install --debug --debug-image=all --boot-directory=/run/media/liveuser/_boot/ /dev/sda
    When I try to boot from the SSD after that, the system displays the following text and hangs (note the single dot on the first line):

    Code:
    .
    kern/disk.c:196: Opening `hd0,msdos1'...
    partmap/msdos.c:188: partition 0: flag 0x80, type 0x83, start 0x800, len 0x200000
    kern/fs.c:56: Detecting ext2...
    kern/disk.c:295: Closing `hd0'.
    In my second test I installed Grub in the Live USB stick with command (note the --disk-module option):

    Code:
    grub2-install --debug --debug-image=all --disk-module=nativedisk --boot-directory=/run/media/liveuser/_boot/ /dev/sda
    When I try to boot from the SSD after that, the system displays the following text but does not hang (note the single dot on the first line and that issuing command ls returns nothing):

    Code:
    .
    kern/disk.c:196: Opening `ahci0,msdos1'...
    kern/disk.c:281: Opening `ahci0,msdos1' failed.
    kern/disk.c:295: Closing `ahci0'.
    kern/disk.c:196: Opening `ahci0,msdos1'...
    kern/disk.c:281: Opening `ahci0,msdos1' failed.
    kern/disk.c:295: Closing `ahci0'.
    error: no such device: 3788f526-875a-4ca1-938c-56aa45c213d8.
    kern/disk.c:196: Opening `hd0'...
    kern/disk.c:281: Opening `hd0' failed.
    kern/disk.c:295: Closing `hd0'.
    error: disk `hd0' not found.
    Entering rescue mode...
    grub rescue> ls
    
    grub rescue>
    In my third test I installed Grub in the Live USB stick with command (note the --modules and --disk-module options):

    Code:
    grub2-install --debug --debug-image=all --modules=ahci --disk-module=nativedisk --boot-directory=/run/media/liveuser/_boot/ /dev/sda
    When I try to boot from the SSD after that, the system displays the following text but does not hang (note the two dots on the first line and that issuing command ls returns nothing):

    Code:
    ..
    kern/disk.c:196: Opening `ahci0,msdos1'...
    kern/disk.c:281: Opening `ahci0,msdos1' failed.
    kern/disk.c:295: Closing `ahci0'.
    kern/disk.c:196: Opening `ahci0,msdos1'...
    kern/disk.c:281: Opening `ahci0,msdos1' failed.
    kern/disk.c:295: Closing `ahci0'.
    error: no such device: 3788f526-875a-4ca1-938c-56aa45c213d8.
    kern/disk.c:196: Opening `hd0'...
    kern/disk.c:281: Opening `hd0' failed.
    kern/disk.c:295: Closing `hd0'.
    error: disk `hd0' not found.
    Entering rescue mode...
    grub rescue> ls
    
    grub rescue>
    Does anybody have suggestions about what to try in the --modules and --disk-modules options? I guess that during grub2-install the disk is in LBA48 mode but during boot BIOS uses older LBA mode.

    Should I try embedding more modules and grub.cfg into core.img?

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